TS2940 Taiwan Semiconductor Company, TS2940 Datasheet - Page 4

• Manufacturer Part Number: TS2940
• Description: 1A Ultra Low Dropout Fixed Positive Voltage Regulator
• Manufacturer: Taiwan Semiconductor Company

TS2940
Application Information (continued)
The next parameter which must be calculated is the
maximum allowable temperature rise, T
calculated by the using to formula:
T
Where: T
Using the calculated values for T
maximum allowable value for the junction to ambient
thermal resistance, θja, can now be found:
θja = T
R
(max) = T
temperature, which is 125
grade parts.
which will be encountered in the application.
R
T
(max) / P
A
J
(max) is the maximum ambient temperature
(max) is the maximum allowable junction
J
(max) – T
D
A
(max)
R
(max) and P
o
C for commercial
R
(max). this is
D
, the
4-6
IMPORTANT: if the maximum allowable value for is
found to be ≥60
for the TO-263 package, ≥150
package, or ≥170
heatsink is needed since the package alone will dissipate
enough heat to satisfy these requirements. If the
calculated value for θja falls below these limits, a
heatsink is required.
o
C/W for the TO-220 package, ≥80
o
C/W for the SOT-223 package, no
2003/12 rev. B
o
C/W for the TO-252
o
C/W